Cable tray

#The present invention relates to cable trays for use with electrical cables.

#Cable trays are used to support electrical cables which run through factories and other structures. Cable trays may have straight and (horizontally and vertically) curved sections to accommodate the installation requirements of a particular setting.

#One type of known cable tray has a pair of parallel side rails or stringers that are interconnected with a plurality of transverse rungs at predetermined intervals along the length of the parallel side rails. Cables are laid on top of the rungs. The rungs are typically attached to the side rails by fasteners, or are welded to the side rails. The parallel side rails may be joined end-to-end by a splice plate or a connecting bar. However, since these cable trays generally do not secure the cables in spaced relation to each other, they may be unsuitable for use with high power cables where there may be a need to keep the cables cool, or to prevent the cables flailing in the event of a fault or short circuit.

#In the figures which illustrate example embodiments of the invention:

#FIG. 1 is a perspective view of a cable tray made in accordance with this invention;

#FIG. 2 is a front view of the cable tray of FIG. 1;

#Referring to FIG. 1, a cable tray 10 has a pair of opposed side rails 12a and 12b to which are attached opposed pairs of lower and upper rungs 14L, 14U. A plurality of cable support blocks 26, 28 are held in place by each pair of rungs, and cables 32 extend through cylindrical openings formed by the support blocks. Vented covers 17 may be attached to the upper and lower rungs 14U, 14L.

#Turning to FIGS. 2, 3, and 3A, each of rungs 14L and 14U has a U-shaped profile which provides a central channel 16 along the length of each rung. An opening 34 extends along the length of each of the two side arms 19 of each rung. The lowermost support block 26L is fitted into the central channel 16 of the lower rung 14L and the uppermost support block 26U is fitted into the central channel 16 of the upper rung 14U. Each rung is positioned so that its openings 34 are aligned with aligned through bores 50 (FIG. 4) in opposed side rails 12a, 12b. A rod 18 runs through each opening 34 in the rungs and through the through bore 50 (FIG. 4) in each of the side rails 12a, 12b. The rods are threaded and a flange nut 20 is threaded to either end of each rod to attach the rungs to the side rails.

#Cable support blocks 26L and 26U are identical in configuration but oriented oppositely. Thus, each of the support blocks 26L, 26U has one straight face 42 (which for block 26L is the lower face and which for block 26U is the upper face) and one face 44 with four semi-circular cut outs 45 (which for block 26L is the upper face and which for block 26U is the lower face). It is the straight face 42 of each block 26L, 26U which is fitted into the channel 16 in a rung 14L, 14U.